Advertisements
Advertisements
प्रश्न
When does a force do work?
Advertisements
उत्तर
A force does work whenever there is a displacement in the direction of force applied.
संबंधित प्रश्न
A boy weighing 40 kgf climbs up a stair of 30 steps each 20 cm high in 4 minutes and a girl weighing 30 kgf does the same in 3 minutes. Compare:
- The work done by them.
- The power developed by them.
When a body is placed on a table top, it exerts a force equal to its weight downwards on the table top but does not move or fall
1) Name the force exerted by the table top
2) What is the direction of the force?
How is kilowatt hour related to joule?
State the condition when a force produces
(i) linear motion.
(ii) rotational motion, in a body.
An engine does 54,000 J of work by exerting a force of 6000 N on it. What is the displacement in the direction of the force?
A force F when acts on a body, displace it by a distance d in a direction at an angle θ with the direction of the force. Write down the expression for the work done by the force.
Derive a relation between the S.I. and C.G.S. unit of force.
A coolie carries a load of 30 kgf through a distance of 500 m in 5 minutes while another coolie B carries the same load through the same distance in 10 minutes. Compare the
(i) work done, and
(ii) power developed. (Take: g = 10md−2)
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
A force of 1 kgf displaces a body by a distance of 10 cm
(i) in direction of force,
(ii) normal to the force
(iii) at an angle of 60° to the direction of the force.
Calculate the amount of work done in each case. (Take: g = 9.8 ms−2 )
